Process communication and runtime.exec()

Question

I need to create a java class that interacts with a non-java application. The non-java application is a spell checking program which reads a misspelling from stdin and writes a list of suggestions to stdout.
I want a java class that will act as a gateway to this application so I can do the following:
JavaGatewayToSpellChecker checker = new JavaGatewayToSpellChecker();
String[] suggestions = checker.checkWord("misssspelling");Here is how I have the class set up so far:
import java.io.*;
public class JavaGatewayToSpellChecker()
    BufferedWriter writer;
    BufferedReader reader;
    public JavaGatewayToSpellChecker()
        try
            String[] cmd = new String[2];
            cmd[0] = "aspell";
            cmd[1] = "-a";
            Runtime rt = Runtime.getRuntime();
            System.out.println("Execing " + cmd[0] + " " + cmd[1]);
            Process proc = rt.exec(cmd);
            writer = new BufferedWriter(new OutputStreamWriter(proc.getOutputStream()));
            reader = new BufferedReader(new InputStreamReader(proc.getInputStream()));
        catch (IOException ioe)
            ioe.printStackTrace();
// no problems yet, as far as I can tell.
public String checkWord(String word)
        String reply = new String();
        try
            writer.write(word);
            String line = reader.readLine();
// I know that a line that begins with one of the following
// characters signals the end of the suggestion list
            while (! (line.startsWith("*") || line.startsWith("&") || line.startsWith("#")))
                reply = reply + line;
                line = reader.readLine();
        catch (IOException ioe)
            ioe.printStackTrace();
String suggestions[] = parseReply();
// code for parseReply() is omitted for brevity, but I
// never get down this far anyway. The code just hangs
// in the loop.
        return suggestions;
    }What am I doing wrong? I have seen a solution using a thread that just runs all the time gobbling the output and either throwing it away or writing it to a file, but I need the output returned so I can parse it and pass it back to the calling method.
I will be really impressed if anyone can solve this problem.
Thanks,
Jon

Answer 1

Well, you guys were no help at all. I spent hours reading the java forums and tried everything under the sun. I had a separate thread read the output and then tried to communicate with that thread using PipedReader/PipedWriter. I can read the output and write it to a file or print it, but I can't bloody pass it back to the calling method. What am I missing??
Finally I just made the class static and decided to exec the entire process everytime I need it. Since I have to spell check a couple hundred thousand strings I'm just going to have to start and stop the process a couple hundred thousand times. This is the most retarded programming solution I have ever come up with. I can't believe the guys who wrote the java.lang.Runtime package couldn't do any better than this. From what I can tell from reading the boards I am not the only person who has struggled with this issue.
There is clearly an elegant solution that anyone with six years of java experience and a week of free time on their hands could come up with, but for those of us who have only been programming since 2001 and who have to get on with life I guess it makes more sense just to let the computer run all night on a dumbass solution than try to divine the solution to this problem.
AAARRGGGHHHH. I just have to rant a bit. I wasted a whole day :(
My solution:
import java.io.*;
public class JavaGatewayToSpellChecker
    public static String checkWord(String word)
        String reply = new String();
        try
            String[] cmd = new String[2];
            cmd[0] = "aspell";
            cmd[1] = "-a";
            Runtime rt = Runtime.getRuntime();
            System.out.println("Execing " + cmd[0] + " " + cmd[1] );
            Process proc = rt.exec(cmd);
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(proc.getOutputStream()));
            BufferedReader reader = new BufferedReader(new InputStreamReader(proc.getInputStream()));
            System.err.println("writing: "+word);
            writer.write(word);
            writer.newLine();
            writer.close();
            String line;
            while ( (line=reader.readLine()) != null)
                reply += line;
            int exitVal = proc.waitFor();
        catch (Exception e)
            e.printStackTrace();
        return reply;
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